VATICAN CITY (CNN) -- Workers have affixed a special chimney to the top of the Vatican's Sistine Chapel, a sign amid the mourning for Pope John Paul II that a new era for the papacy is about to begin.

The stovepipe, erected Friday and connected to a pot-bellied stove in the chapel, will provide a signal to the world when a new pontiff is selected.

Once the conclave begins Monday, the 115 cardinals expected to take part will vote up to four times each day until a pope is selected.

At the end of each morning and afternoon session, the ballots from that session will be burned and chemicals added to provide color.

If a pope has been chosen -- which requires a two-thirds majority -- the smoke will be white. If not, it will be black.

CNN Vatican analyst John Allen said Friday "a whole lot" of politicking was going on in advance of the conclave, which starts the day after the end of the nine-day mourning period for John Paul II.

Cardinals agree that the next pope must be charismatic and able to reach worldwide audiences, some cardinals said. John Paul II spoke more than a dozen languages, attracting enormous crowds for his speeches. He was also very media savvy, using new technology to reach worldwide audiences.

But there are many differences among the cardinals over where the next pope should stand on key issues, Allen said.

John Paul II was staunchly conservative on issues of sexuality and the role of women in the church.

But on topics such as war, social justice, and inter-religious dialogue, he was considered centrist, even progressive, Allen said.

There has been speculation about numerous potential candidates, called "papabile," led by German Cardinal Joseph Ratzinger, the deacon of the College of Cardinals who delivered the homily at John Paul's funeral.

But some question whether it would be better to choose a pope from Africa or Latin America.

Allen said a cardinal told him the participants hope the conclave will be long enough to make clear there was a full discussion, but brief enough to avoid suggestions of a behind-the-scenes battle.